1. Field of Invention
The present invention relates to amine salts of N-triazolyl-hydrocarbyl succinamic acids and to lubricating oil compositions containing same.
The operational efficiency and reliability of an internal combustion engine is vitally dependent on the lubricating oil composition employed in the engine. The oil composition must provide effective lubrication over a wide temperature range including cold and occasionally sub-zero engine starting temperatures, low temperature stop-and-go driving conditions, and high speed, high engine operating temperatures. An effective lubricant must also exhibit thermal stability, anti-wear, load-carrying and anti-oxidation properties for extended operating periods. In the case of gas turbine engines, the lubricating oil composition is subjected to internal engine operating temperatures ranging as high as 500.degree. F. or higher which puts an extreme stress on the stability of the oil.
Because of the noted requirements, lubricating oil compositions are constantly under investigation to improve their effectiveness for providing the required properties as well as to extend the length of their service life. Additive candidates are continuously being introduced into base oils to form new experimental lubricant compositions and the more promising new lubricants identified in screening tests are further tested to determine their effectiveness under representative operating conditions.
2. Description of the Prior Art
It is known in the art that the addition of an azole compound to a synthetic lubricating oil composition will improve the copper corrosion properties of the lubricating composition. The azole type additives, including such compounds as 3-amino-triazole and 4-amino-triazole, are known as copper passivators. It has been theorized that these compounds attach themselves to the surface of the copper substrate to deactivate or reduce the corrosiveness of the copper metal that is in contact with the hot lubricating oil composition. Examples of this are U.S. Pat. No. 4,064,059, U.S. Pat. No. 3,756,952, U.S. Pat. No. 3,247,111 and British Pat. No. 1,180,387 which are incorporated herein by reference.
Despite the extensive art relating to lubricating oil compositions, there still remain problems which are not solved by the compositions known in the art. There is still a need for additives which lead to the production of lubricating oil compositions with improved oxidation resistance, rust inhibiting and metal deactivating properties. None of the prior art lubricating oil compositions which employ azole type additives are completely satisfactory for these purposes.
Accordingly, it is an object of this invention to provide an amine salt of an N-triazolyl hydrocarbyl-substituted succinamic acid which can be incorporated into a lubricating oil composition.
It is also an object of this invention to provide a lubricating oil composition containing the amine salt of an N-triazolyl hydrocarbyl-substituted succinamic acid which exhibits outstanding rust inhibiting properties in addition to thermal and oxidation stability and copper metal passivity.
The advantages and objects of this invention will become apparent to those skilled in the art from the following discussion and accompanying examples.